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I modified a set of stock forks caps awhile ago with standard schrader valves.
Chucking in the lathe, drilling the appropriate sized hole. Then epoxy a schrader valve in each cap, lock nut on each end. (The valve stems were left over from old MC tubes.)
I looked at installing aftermarket pre-load adjusters and wasn't thrilled at what was out there..
More thought on the spring pre-load adjusters, your adding more pressure to the springs (more sag as they wear/age). Using air, infinitly adjustable, NO added pressure / weight on the springs and actually helping the springs work less(air is helping hold the bike up)
Some preliminary #'s;
Static sag bike only, 32 mm before-after with 17 PSI = 15mm's
sag with 200 lb rider-after with 17 PSI, 27mm's
Some notes;
Many on/off road bikes (IE, KLR's) use added air for off road use for decades.
Definitly picked the front up some.. Its not too harsh and still soaks up the bumps well. Definitly less nose dive with hard front braking.
It is a very small area in the fork your adding air to, thus adding air is done VERY QUICKLY if using an air compressor. (A quick shot can easily put 40 PSI in the forks.)
I made on the lathe and tried to install 18 mm thick aluminum spacers over the weekend to raise static sag. Spacers came out great but too much pre-load to install them. .
I've done research (and used air ONLY forks years ago on my YZ's) and found where once the fork seal RETAINER is removed, a very high amount of air pressure (100+ PSI) can pop the seals out without disassembly.
I can increase air pressure to raise the front end more but found 17-18 PSI to work for me without adding too much stiffness.. The low PSI should not make any sealing issues. (We did run long travel MX forks with AIR ONLY ((NO springs-less un-sprung weight)) decades ago with NO issues, AMA sanctioned moto cross so they did get a work out...
Last pic is that of the digital gauge(very accurate and well made)
This mod can be done with the use of a drill press/ drill as well..
Overall, I'm very happy with the mod. I do have to check the headlight adjustment once dark but it still should be pretty close.
Chucking in the lathe, drilling the appropriate sized hole. Then epoxy a schrader valve in each cap, lock nut on each end. (The valve stems were left over from old MC tubes.)
I looked at installing aftermarket pre-load adjusters and wasn't thrilled at what was out there..
More thought on the spring pre-load adjusters, your adding more pressure to the springs (more sag as they wear/age). Using air, infinitly adjustable, NO added pressure / weight on the springs and actually helping the springs work less(air is helping hold the bike up)
Some preliminary #'s;
Static sag bike only, 32 mm before-after with 17 PSI = 15mm's
sag with 200 lb rider-after with 17 PSI, 27mm's
Some notes;
Many on/off road bikes (IE, KLR's) use added air for off road use for decades.
Definitly picked the front up some.. Its not too harsh and still soaks up the bumps well. Definitly less nose dive with hard front braking.
It is a very small area in the fork your adding air to, thus adding air is done VERY QUICKLY if using an air compressor. (A quick shot can easily put 40 PSI in the forks.)
I made on the lathe and tried to install 18 mm thick aluminum spacers over the weekend to raise static sag. Spacers came out great but too much pre-load to install them. .
I've done research (and used air ONLY forks years ago on my YZ's) and found where once the fork seal RETAINER is removed, a very high amount of air pressure (100+ PSI) can pop the seals out without disassembly.
I can increase air pressure to raise the front end more but found 17-18 PSI to work for me without adding too much stiffness.. The low PSI should not make any sealing issues. (We did run long travel MX forks with AIR ONLY ((NO springs-less un-sprung weight)) decades ago with NO issues, AMA sanctioned moto cross so they did get a work out...
Last pic is that of the digital gauge(very accurate and well made)
This mod can be done with the use of a drill press/ drill as well..
Overall, I'm very happy with the mod. I do have to check the headlight adjustment once dark but it still should be pretty close.
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